Centrifuge method and apparatus



March 11, 1932, H. s. (:05

CENTRIFUGE METHOD AND APPARATUS Filed March 31,. 1930 3 Sheets-Sheet 1 INVEN TOR. fiarnzsoxr 560a March 1, 1932. H. 5. col;

CENTRIFUGE METHOD AND APPARATUS Filed March 31, 1930 3 Sheets-Sheet 2 v 6 w M M Mm www I T .m WM H :EIE E March 1, 1932. H. s. COE 1,847,751

CENTRIFUGE METHOD AND APPARATUS v Filed March 31, 1930 s Sheets-Sheet s :E'IIIEL 4 INVEN TOR. Ha/r/Jafl 6. 60a

ATTORNEYS.

Patented Mar. 1 1932 A V 1 UNITED STATES PATENT ounce HARRISON S. ODE, OF PALO ALTO, CALIFORNIA, ASSIGNOR '10 HER-CO CENTRIFUGAL SEPARATOR 00., LTD 01'! SAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALI- FORNIA CENTRIFU'GE METHOD AND APPARATUS Application filed March 81, 1980. Serial No. 440,592.

This invention relates generally to centrifuge methods and apparatus such as are employed for separating components of differentspecific gravities from fluid feed material.

It is an object of the present invention to devise a centrifuge apparatus and method of the above character which will make possible a substantial degree of control over the char-' acteristics of the discharge material containing or forming the heavier components separated from the feed material. Thus the preferred method and apparatus herein disclosed makes it possible to maintain the density of the discharge substantially constant or within predetermined limits, practically independently of the rate with which feed material is supplied and of variations in the characteristics of the feed.

It is a further object of the invention to devise a centrifuge method and apparatus which will permit automatic operation to control the density of the discharge. In attaining this object the invention is characterized by automatic control of the rate of introduction of an additional material into the centrifuge chamber, the rate of introduction being determined by the density of the discharge.

It is a further object to devise a centrifuge method and apparatus which will operate with a minimum of drivingpower, and which will not clog when used with feed material containing granular or gritty components, such as sand.

It is another object of the invention to devise a centrifuge apparatus in which wear upon certain parts is reduced to a minimum.

Further objects of the invention will appear from the following description in which the preferred embodiments of the invention have been set forth in detail in conjunction with the accompanying drawings. It is to be understood that the appended claims are to be accorded a range of equivalents consistent with thestate of the prior art.

Referring to the drawings:

Figure 1 is a side elevational view in cross section illustrating a centrifuge apparatus incorporating principles of the present invention.

- trifuge chamber 11.

Fig. 2 is a cross sectional view taken along the line 22 of Fig. 1.

Fig. 3 is a diagrammatic view in side elevation illustrating the mode of operation of the apparatus shown in Figs. 1 and 2.

Fig. 4 is a diagrammatic view in side elevation illustrating a modified form of apparatus or system incorporating principles of the invention.

Fig. 5 is a detail illustrating a suitable construction for the discharge nozzle.

The method of the invention can best be understood 'by a detailed description of the apparatus illustrated in the drawings. Thus referring to Figs. 1 and 2, there is shown a centrifuge machine which is conventional to the extent that it includes a rotary cen- This chamber can be formed by the truncated sections 12 and 13, which are shown secured together by an annular portion 14. F orrotating the chamber about its axis, a shaft 16 extends downwardly centrally of the same, and is secured to a closure member or disc 17 extending across the lower portion of section 13. The upper end of shaft 16 has a suitable flexible coupling to a drive shaft 17, andis also provided with a suitable universal bearing 18.

Feed material to be treated is preferably introduced into the lower portion of chamber ll, and as an example of means permitting such introduction, adisc 21 is mounted in spaced relationship with respect to disc 17 so as to form a laterally extending passageway 22 communicating at its periphery with the chamber 11. Conduit 23 extends upwardly from disc 21 and concentrically with respect to shaft 16, and the upper open end of this conduit receives the lower end of a relatively stationary conduit 24. Launder 26 serves to discharge fluid feed material into the upper end of conduit 24, whereby this material is delivered to conduit 23 and to passageway 22.

The upper portion of chamber section 12 is provided with a collar 27 which is spaced about the conduit 24, and which forms a. weir over which lighter separated material is discharged. The heavier separated material is preferably discharged from the outermost charge nozzles 28 are mounte peripheral portion of the chamber 11. Thus a plurality of circumferenti-all spaced disupon annular portion 14, and the passages 29 afforded by these nozzles communicate with the outermost peripher of chamber 11. These nozzles are pre erably formed as shown in Fig. 2, so as to ischarge tangentially but backwardly relative to the direction of rotation. Thus the material discharged from these nozzles can be described as forming backwardly directed reacting jets of material. To form arestricted discharge port or orifice for each nozzle, an aperturec disc 31 made of suitable material such as' resilient rubber, can be detachably mounted upon the end of each nozzle by means of a threaded ring 32, (Fig. 5).

Forcertain reasons, as for example to facilitate introduction of a material into the centrifuge chamber in addition to the fluid feed, the rotary parts described above are positioned within a suitable housing or tank 36. Spaced conical plates 37 and 38 mounted upon this tank form a space into which lighter material flowing over collar 27 is discharged, this material being removed thru conduit 39. A portion of the heavier material discharged thru nozzles 28 falls directly into and is collected in the lower portion of tank 36. In order to introduce material collected in tank 36 into the centrifuge chamber in addition to the feed material, a pump portion 39 is mounted upon the lower portion of the centrifuge chamber. This pump portion can be conveniently formed of a frustroconical section 41, having its lower smaller end adapted to be immersed in the material collected in tank 36 and having its upper larger end mounted upon the lower end of chamber section 13.- Pump portion 39 serves to lift material in which its lower end is im-- mersed, and in order to deliver this pumped material into apredetermined zone of chamber 11, a plurality of outwardly extending pipes 42 are provided. The inner ends of v these pipes are mounted upon plate 17 and communicate with the inner space of pump portion 39, while their outer ends deliver material to a zone extending about the periphery of the chamber. The number of pipes provided is preferably equal to the number of nozzles 28, and each pipe is directed towards its particular corresponding nozzle, as shown in Fig. 2.

The action taking place within the centrifuge chamber during operation of the machine, will be explained in greater detail, but in general it may be stated that I have found that by introducing a proper material thru portion 39, and by controlling the rate of introduction, the density of the material discharged thru nozzles 28 can be controlled. Thus if for an additional material a portion of the discharge material is returned into the centrifuge thru pump portion 39, an increase in the rate of introduction of such an additional material for a given feed will tend to increase the density of the discharge thru nozzles 28, and conversely a decrease in the rate of introduction of the additional material will cause a corresponding decrease in the consistency or densit of the discharge. In many instances it is esirable to operate centrifuge apparatus. in such a manner that the density of the material finally removed, containin the heavier separated components of the cod, is of substantially constant density or of a density between certain predetermined values. \Vith the apparatusof F i s. 1 and 2, such-a control is made automatlcally by the use of specific gravity testing means indicated generally at 44. In the specific form shown means 44 consists of a receptacle 46, which is sup ported by one end of a fulcrumed beam 47 ounter balancing weight 48 upon beam 47 is adjustable for different specific gravities. A pipe 49 within the receptacle has its lower end open, and its upper portion connected to a discharge pipe 51. An overflow pipe 52 is connected with the upper portion of receptacle 46, and has a common discharge with pipe 51. Since in the modification shown in Figs. 1 and 2 a portion of the discharge material is returned to the centrifuge chamber, a receiver 53 is provided adapted to collect material discharged from nozzles 28, and which extending about the inner wall of tank 36 for only a portion of the tanks inner periphery. Pipe 54 serves to deliver the material collected in receiver 53 into the upper portion of container 46. Cooperating with the discharge of pipes 51 and 52, there is a bafile 56 which is adapted to divert the material between a container 57 and container 58 which communicates with the lower portion of tank 36 thru a trough 59. Material diverted into container 57 can be removed thru pipe 59.

The preferred manner of operating the apparatus of Figs. 1 and 2, can best be explained by reference to Fig. 3. It is presumed that feed material containing components of different specific gravities is being introduced into the centrifuge chamber 11 thru conduit 23 and passageway 22. A mass of material being subjected to contrifugal force is therefore maintained within the chamber, and an overflow of lighter separated material occurs over collar or weir 27.

of tank 36. Since the lower end of pump portion 39 is immersed in the material in tank 36, this material is continuously pumped upwardly and delivered into pipes 42, a sufficient fluid head being established to cause acontinuous discharge from the outer ends of these pipes into the centrifuge chamber 11. Sincethe material delivered thru pipes 42 is discharge material which has previously been treated in the centrifuge, the ratio of heavier to lighter components in this additional material is substantially greater than the ratio of heavier to lighter components in the. original feed. Thus the introduction of such an additional material thru pipes 42 serves in effect to substantially increase the total rate of introduction of heavier components into the centrifuge chamber relative to the rate of introduction occurs over bafile 56 into trough 58, from of lighter components.

By continuously introducing such an additional material in this manner, the space within the centrifuge chamber in which centrifugal separation is taking place-is confined to a zone spaced from the outer periphery of the chamber. Thus in Fig. 3 three different zones, A, B, and C, have been indicated as formed within the centrifuge chamber. Zone A is formed by lighter separated material being removed over weir 27, zone B represents a space in which centrifugal separation is taking place between lighter and heavier separated components, and the outer zone C is formed by material of discharge consistency. The material discharged thru nozzles 28 consists of a mixture of the heavier components directly separated from the feed, and the additional material introduced thru pipes 42. Since the tangential velocity of the additional material introduced into the centrifuge chamber at the ends of pipe 42 differs from the tangential velocity of heavier components in zone C adjacent the ends of pipe 42 separated directly from the feed, a rapid vertical movement of material occurs adjacent the end of pipe 42 and adjacent to the points of communication between nozzles 28 and the centrifuge chamber. Thus a region of violent agitation is formed adjacent each nozzle 28 in the centrifuge chamber, and the pockets occupied by these regions of agitation are effectively scoured and kept free of accumulated or packed solids. It is therefore characteristic of my apparatus that the discharge nozzles will not become clogged with packed material, even though the apparatus is being utilized on feed material containing gritty or granular components, such as sand. It should be noted however that the regions of agitation are confined to the annular zone C formed of material of discharge consistency, and since zone C is entirely outside zone B, proper separation action is not detrimentally affected. Clogging of the discharge nozzles and ports is also prevented"becauseofthe relatively large amount of material passing thru the same.

That part of the material which is continuall diverted thru conduit 54, is continuously elivered to'receptacle 46. Assuming a certain given setting of count-erbalancing weight 48, corresponding to a certain desired specific gravity or densit when a mass of material of a given weig t is within receptacle 46, abalance is established and a continual discharge of material from receptacle 46 occurs thru pipe 51. A certain amount of overflow also occurs thru pipe 52, in order to keep a. substantially constant volume of material within the receptacle. .Assuming now that the specific'gravit or density of the material is too light for nal removal thru pipe 59, receptacle 46 assumes an elevated position in which the discharge from pipes 51 and 52 which it returns to the lower portion of recep tacle 36. Therefore under certain conditions all of the material discharged from the nozzle 28 is returned into the centrifuge thru pump portion 39. Since feed material containing eavier components is being continually introduced into the centrifuge, under such conditions it is evident that the amount of material in tank 36 will increase, thus causing pump portion 39 to deliver a greater quantity of additional material into the centrifuge chamber thru pipes 42 because of the higher level within the tank. Such an increase in the rate of introduction of additional material will tend to increase the density of the discharge from nozzles 28 until the desired density is attained. As the discharge material approaches the desired density, the heavier material being discharged to receptacle 46 tends to lower this receptacle, until a part of the material from pipes 51 and 52 is being diverted into'container 57, and a part back into the tank 36. Under an ideal condition of equilibrium, the material discharged from nozzles .28 is of the desired density and a suflicient amount of the discharge material is being returned into tank 36 fromv the specific gravity testing means 44 to return material into the centrifuge chamber at a rate proper V to maintain the desired densit Assuming that a change takes place in tie rate of introduction offeed material, or that the characteristics of the feed material are altered, the tendency of such variations or changes to effect a corresponding change in the density of the discharge material is immediately compensated for by the specific gravity testing means 44. In other words according to the method of my invention, the rate of introduction of material introduced thru pipe 42 is controlled according to thedensity of the discharge material and independently of variations in the rate and characteristics of the feed. Assuming that the introduction of feed ceases'entirely over a given period, spe- 57 and withdrawn thru pipe 59, until the density of the discharge material decreases to the desired value. While in most instances it is desirable to keep the discharge material at a substantially constant specific gravity, it is evident that by proper operation the specific gravity of the discharge material can be simply kept between certain definite upper and lower limits.

It is evident that instead of having beam 47 move gradually to different positions responsive to a change in the specific gravity of the discharge, it can be arranged in such a manner as not to balance in an intermediate position, but to oscillate between definite limits 60. With such a mode of operation the position of receptacle '46 is intermittently and abruptly shifted between raised and lowered positions. In the raised position all of the material from receptacle 46 is returned over the wall 516, while in the lowered position all of the material is diverted to the final discharge pipe 59. This mode of operation is advantageous because by counting the oscillations of the receptacle over a given period, and by determining the rate of flow into the receptacle, it is a simple matter to check the approximate rate of return to the centrifuge chamber or the rate of discharge thru pipe 59. In an actual test of the invention described above, the apparatus was utilized for the separation of sand from a fluid feed containing a mixture of clay and sand in water. The apparatus functioned automatically to deliver a mixture of sand and water to pipe 59 of sub stantially constant specific gravity and sub- 50 stantially free of the lighter clay. Variations in the rate or characteristics of the feed were immediately compensated for by the specific gravity testing means 44. In fact the feed could be made intermittent without clogging the machine and without causing the heavier discharge material to be mixed with substantial quantities of clay.

It is evident that the consumption of power may be an important item in a centrifuge installation, particularly where relatively large quantities of material are passing thru the centrifuge chamber, as in the present invention. In my apparatus the power consumption is maintained at a minimum because of the use of backwardly directed nozof final discharge. Such continued outward movement has been found highly desirable to prevent a clogging of the machine, particularly where handling feed material containing gritty or granular components such as sand. It will also be noted that the points of discharge of pipes 42 are located outside the zone of separation B and between this zone and the points of final discharge from nozzles 28.

With respect to the regions of agitation produced within the centrifuge chamber thru introduction of the additional material, these regions can be kept within reasonable limits, and the centrifuge operated with less power consumption, by imparting a substantial amount of energy of rotation to the additional material introduced thru pump portion 39. In the form described above, this function is performed by pipes 42 which deliver the additional material at substantially the same absolute tangential velocity as the rotative velocity of the outer ends of the pipes.

In that form of the invention previously described the additional material'introduced into the centrifuge chamber is heavier material previously discharged from the centrifuge. In Fig. 4 I have illustrated a centrifuge apparatus in which the additional material can be from any convenient source of supply. In this case the rotating parts of the apparatus are similar to the rotating parts described with respect to Figs. 1 and 2, and these parts are likewise disposed within a suitable tank 61 corresponding to tank 36 of Fig. 1. In place of directlydischarging a part of the material from nozzles '28 into tank 61, all of the discharge material is collected by a suitable receiver 62. The additional material for introduction into the centrifuge chamber by way of pump portion 39, is delivered into tank 61 from a suitabe storage reservoir 63, thru'pipe 64. Material collected by receiver 62 is discharged into a receptacle 65 by way of pipe 66. Receptacle 65 is provided with an overflow pipe or spout 67 which discharges into a collector 68, from which the desired discharge material is removed. Recept'acle 65 is carried by one end of a fulcrumed beam 67, this beam being counter balanced by adjustable weight 71. A valve 72 serves to'control flow of material from reservoir 63 to tank 61, and this valve is controlled by a counterbalanced lever 73.

Member 74 mechanically connects lever 73 with receptacle 63.

In operating the apparatus of Fig. 4, material of proper characteristics, as for example material of discharge consistency, is stored in reservoir 63, and 1s normally delivered to tank 61 thru pipe 64. Assuming that feed material is also being introduced into the centrifuge chamber 11, the centrifuge 0 rates in the same manner as apparatus of igs. 1 and 2 in that pump portion 39 serves to continually introduce material from tank 61 into the centrifuge chamber, in addition to the feed material. Discharge material delivered from nozzles 28 flows into receptacle 65, and the weight of this material in rece tacle 65 determines the vertical position of t e receptacle and the setting of valve 72. Assuming that the discharge material is too light in specific gravity, receptacle 65 tends to take an elevated position so that valve 72 tends to increase the flow of additional material from reservoir 63, thus increasing the rate of.

stantially constant. While the apparatus of Fig. 4 may be preferred for certain mstallations, the apparatus of Figs. .1 and 2 is generally more desirable since its operation does not depend upon the maintenance of a stored supply of additional material from an aux liary source.

s pointed out above there are certain advantages secured by discharging the heavier material thru backwardly reacting jets. It is also characteristic of this arrangement that wear upon the side walls of tank '36 upon which the heaviermaterial is discharged by nozzles 28 is reduced to a minimum due to the reduced relative velocity of the discharge material with respect to the tank. Likewlse splashing of discharge material upon nozzles 28 after discharge will cause lesswearof these parts. Reducing the veloclty w1th which the discharge material impacts with the use of a centrifuge chamber having provision for the discharge of material containing or forming heavier components centrifugally separated from a fluid feed, said method comprising testing the specific gravity of said discharge material, returning discharge material back into said chamber, and controlling the rate of return according to the density of said discharge material.

' 3. In a centrifuge method characterized by the use of a centrifuge chamber having provision for the discharge of material containing or v forming heavier components centrifugally separated from a fluid feed, said method .comprising testing the specific gravity of said discharge material, returning discharge material bac into said chamber, and controlling the rate of return according to the density of said dischar e material, a eater amount of said material being returne when the density falls below a given value and a lesser amount being returned when the density exceeds a given value.

4. In a centrifuge method, the steps of subjecting a confined mass of material to centrifugal force, feeding fluid feed material to said .mass, the feed containing light and heavier components, maintammg 1n the mass an outer zone of dischar e consistency containing heavier separate components, said zone being maintained, about an inner zone in which centrifugal separation is taking place, and continually discharging material from the outer eriphery of said outer zone by movement 0% the material from said zone in a direction which is always outwardly relative to the center of said mass.

5. In a centrifuge method, the steps of subjecting a confined mass of material to centrifugal force, feeding fluid material to said mass, said fluid material containing light and an outer zone of discharge consistency containing. heavier separated components, said zone being maintained about an inner zone in which centrifugal separation .is taking place, and continually discharging material from the outer. periphery of said'outer zone along paths of movement which are directed back-' wardly away from the direction of rotation but-which do not return towards the center of the mass before final discharge.

6. In a,centrifugalmethod,the steps of subjecting a confined mass of material to centrif-ugal force by rotationof the same about an axis located centrally of the mass, feeding fluid feed material containing components of different specific gravities to said mass, disheavier components, maintaining in the mass charging heavier centrifugally separated material from the outer periphery of the mass in such a manner as to form reacting jets of discharge materialdirected backwardly and substantially tangentially with respect to the direction of rotation, the paths of movement of heavier components toward said jets being always outwardly relative to the axis of rotation, and introducing additional material into said mass to maintain a zone of material of discharge consistency extending inwardly from the outer periphery of said mass, said additional material being continuously introduced into said zone.

7, In a centrifuge apparatus, a centrifuge chamber, means for introducing feed-material into said chamber, means for effecting discharge of material containing or forming heavier separated components of the feed. and means responsive to the density of said discharge for returning a portion of the dis charge back into said chamber at a controlled rate.

8; In a centrifuge apparatus, a centrifuge chamber, means for introducing feed material into said chamber, means for effecting discharge of material containing heavier separated components of the feed, specific gravity testing means adapted to receive discharge material, and means controlled by said specific gravity testing means for returning a controlled amount of discharge material back into said chamber.

9. In a centrifuge apparatus, a rotary chamber having nozzles communicating with its outer periphery for the discharge of material containing or forming heavier separated components, means for introducing feed material into said chamber, said noz zles being directed backwardly and substantially tangentially with respect to the direction of rotation of the chamber and serving to conduct material outwardly to points of discharge from the periphery of the chamber, said points of discharge being outside the radius of said chamber, and means for maintaining a zone of material of discharge consistency adjacent the outer periphery of the chamber and surrounding a zone of separation, said means comprising means for introducing an additional material into said chamber outside said zone of separation.

10. In a centrifuge apparatus, a rotary rotary chamber having nozzles communicating with its outer periphery for the discharge of material containing or forming heavier sparated components, means for introducing feed material into said chamber, said nozzles being directed backwardly relative to the direction of rotation and serving to conduct material outwardly to points of discharge from the periphery of the chamber, and means for maintaining'a zone of material of discharge consistency adjacent the outer periphery of the chamber and surrounding a zone of separation, said means comprising means for returning material discharged from said nozzles into said chamber outside said zone of separation.

11. In a centrifuge apparatus, a rotary centrifuge chamber or bowl, a structure surrounding the outer periphery of said bowl, and nozzles upon the bowl adapted to discharge heavier separated material upon said structure, said nozzles being formed to provide backwardly reacting jets to minimize wear on the inner walls of said structure.

12. In a centrifugal method, the steps of subjecting a confined mass of material to centrifugal force by rotation of the same about an axis located centrally of the mass, whereby a zone of centrifugal separation is formed within the mass, feeding fluid material containing relatively heavy solid components to said mass, discharging material containing said solid components from the outer periphery of the mass in such a manner as to form reacting jets of discharge material directed backwardly and substantially tangentially with respect to the direction of rotation, the path of movement of said components toward said jets being generally outwardly relative to the axis of rotation, whereby a substantial amount of kinetic energy of the discharge material is recovered and whereby clogging is prevented, and con-v tinuously returning a portion of the discharge material back into said mass at a point located outside said zone of separation and separately of the feed.

13. In a centrifuge apparatus, a rotary chamber having nozzles communicating with its outer periphery for the discharge of material containing or forming heavier separated components, means for introducing feed material into said chamber, said nozzles being directed backwardly and substantially tangentially with respect to the direction of rotation of the chamber and serving to conduct material in a generally outwardly direction to points of discharge from the periphery of the chamber, said points of dis charge being outside the radius of the chamber, and means for continuously returnin material discharged thru said nozzles bac into said chamber separately from the feed at points located outside the zone within the chamber within which centrifugal separation takes place.

14. In a centrifugal method, the steps of subjecting a confined mass of material to centrifugal force by rotation of the same about the axis located centrally of the mass, whereby a zone of centrifugal separation is formed within the mass, feeding fluid material containing relatively heavy solid components to said mass, discharging material containing said solid components from the outer periphery of the mass in such a manner as to form reactive jets of discharge material directed backwardly and substantially tangentially with respect to the direction of rotation, whereby a'substantial amount of kinetic energy of the discharge material is recovered and whereby clogging is prevented, and continuously returning a portion of the discharge material back into said mass separately from the feed at a point located outside said zone of separation, said return being effected in such a manner as to cause agitation within said mass outside said zone of separation; 4

15. In a centrifuge apparatus, a centrifuge chamber adapted to receive a fluid feed material and to discharge heavier material centrifugally separated from the feed, means for continuously introducing material in said chamber in addition to the feed material, a source of said additional material substantially independent of the discharge, and means for regulating flow of said additional material from said source to said introducing means according to the specific gravity of the discharge material.

16. In a centrifuge apparatus, a centrifuge chamber adapted to receive a fluid feed material and to discharge heavier material centrifugally separated from the feed, means for continuously introducing a ma erial in said chamber in addition to the feed material, a storage reservoir for said additional material, and means for regulating flow of said additional material from said reservoir to said introducing means according to the specific gravity of the discharge material.

In testimony whereof, I have hereunto set my hand.

HARRISON S. COE. 

